This great round-up of the solid-state relays currently on the market was posted by MikeCasino to TheHammondZone.
Fast stop slow switching method (extra board for 122 using any S.P.D.T. center off switch ), eliminates the 12AU7 switching tube in the 122 family, standard cabling compatible with stock Leslies using the tremolo / chorale switching method but not compatible with stock Leslies using the tremolo / stop / chorale switching method in stop mode (the stock amp will still remain on fast when you have the switch on stop). Mounting location is in place of the mechanical relay. To use the stop function, a tremolo / stop / chorale switch is used in place of the tremolo chorale switch. The .1mfd cap removal is required.
Switching scheme: apply a common-mode DC bias on the input of greater than 25 volts for slow; apply zero volts for fast; apply from 9 to 18 volts for off. Note that if you plug the relay into a stock control kit for a 122, you'll get normal two-speed (fast/slow) operation.
The Mark IIa Solid State relays for Leslie 122 and 147/251 provide noiseless, quick and extremely reliable motor control. Installation is simple - they are 100% compatible with existing Leslie control circuits and no additional wiring is required from the console. All necessary materials for installation (except the three position switch) and complete instructions are provided. As a bonus for 122 users, switching time with this device is virtually as fast as the 147. Our 122 relay also makes converting 147 amplifiers to 122 specs a snap. The relay control tube is eliminated, as are a number of other components! For the 122 version, an optional, low cost ($2.00) board interfaces with the TREK II TS2-3, or any S.P.D.T., center off switch. The 147/251 version will interface with the TREK II TS2-3 as well. The 122 version will operate on any voltage from 80 - 300 and any frequency from 25hz to 80hz. The 147/251 version operates from 80 - 240 vac. Either will operate on any frequency encountered. If the console switching is modified for tremolo-off-chorale operation, all Leslies used must be equipped with EIS relays. Although no damage to a stock Leslie will occur, switching will be erratic.
All of our solid state relays are totally compatible with legacy Leslie switch kits. They will function exactly as the stock relay, minus noise and clicks and last virtually forever. If you opt for 3 speed operation, all Leslies must have our relay, however, if used as a replacement two-speed relay, go ahead and run them together.
The interface board for the 122 version allows the use of the TREK II TS2-2, ETS2-2, or any S.P.D.T. center off switch to obtain Chorale - Off - Tremolo. The 147 version has software that makes this board unnecessary.
Either version can provide Chorale - Off - Tremolo with a three position switch as used in the Main - Ensemble - Echo Leslie switches. Instructions and the necessary diode are included with the relay.
In the 122 version, a 33V to 36V 1 watt zener diode may also be added to stock Leslie 8000 style kits to decrease switching time. Stop mode requires a 12V zener diode in switching circuit.
If you install the tremolo control circuit in the pre-amp, use a 33V - 36V 1 watt zener diode to ground, in parallel with the 47K, 1W resistor. The cathode (banded) end goes to the resistor junction. This limits the switching voltage to the zener value, prevents the momentary off condition when switching from chorale to tremolo and greatly decreases the switch response time, almost as fast as a 147 (A.C.) relay. It also prevents core saturation in the output transformer.
Fast slow switching method standard cable, compatible with stock Leslies. Eliminates the 12AU7 switching tube in the 122 family. Mounting location is in place of the mechanical relay. The .1mfd cap removal is not required.
Are you tired of listening to that nasty "click" and "snapping" sound you get every time you switch your Leslie® from slow to fast? Replace that old and noisy mechanical relay with a silent Hamptone solid state relay. Unlike the cheaper and simpler designs, the Hamptone solid state relays are optically isolated to insure safe, reliable operation and will also work properly if using a Hamptone MK1B Motor Control. The Hamptone solid state relays are available for the 147 type and the 122 type Leslies®. The Hamptone relay circuit employs two independent logic controlled solid state switches, one for the fast motors and one for the slow. The solid state switches are designed such that they only open or close when no current is flowing through the motors. This also eliminates the possibility of motor switching noise coupled into the audio circuits. Logic circuitry converts the voltage originally used to activate the mechanical relay to a logic signal that powers the appropriate motors.
Standard cable, use fast stop slow switching method, not compatible with stock Leslies. Switching kit for 122 type (8000, 6122 kit ect.) not needed. Mounting location is in place of the mechanical relay.
Switching scheme: Sinking (utilizes pin # 5 to control switching) 0V (closed) fast, open stop, 220K to Ground is slow.
The Hamptone SSR-3X was especially designed to turn "dual-speed" Leslie speakers into a 3-speed off/slow/fast unit using a single 3-way switch. This is accomplished by referencing the signal wire to ground. No more high voltage AC switching (147 type) or DC (122 type) on the audio line. When installed, the 147 series amp will stay unbalanced and the 122 series amps will stay balanced. If you need to stay compatible with other stock 122 or 147 series amplifiers, choose one of our other solid-state relays. This unit works flawlessly!
A jumper selects 147 or 122 operation. And supports the EIS stop mode switching in both cases. Onboard logic power supply - does not use the filament supply from the amp. A second jumper selects between the coast or braking mode. All software based. Three visual indicators (LED'S) indicate power and speed status. Eliminates the 12AU7 switching tube in the 122 family. The .1mfd cap removal is required. Mounting location is in place of the mechanical relay.
Switching scheme: Sourcing (Standard), 0-8.5 VDC fast, >13.5VDC slow, and 8.5-13.5VDC stop.
Easy installation, vendors need to stock one part.
The content of this page is Copyright (C) 2000, 2001, 2002 Geoffrey T. Dairiki and
the other authors of the content, whoever they may be.
This is free information and you are welcome redistribute it
under certain conditions; see
http://www.dairiki.org/HammondWiki/opl.html for details.
Absolutely no warrantee is made as to the correctness of
the information on this page.